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diy solar

Schneider system design wasteland......no one knows anything.....

pvdude

Solar Enthusiast
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Location
Florida
I want to add more PV panels to obtain more power for my inverter to use.
I understand the inverter I have is capable of 6800 watts continuous.
6800 watts does not seem to be possible with one single Conext XW MPPT 100-600 Charge Controller.
I need help in designing a system upgrade to obtain the 6800 watt power level.

I don’t know what to buy, and the 3 vendors I have communicated with can only take orders,
they do not know anything about Schneider equipment, they just sell it.

I have this equipment:
Conext XW Pro 6848
Conext XW+ Mini Power Distribution Panel
Conext SCP - System Control Panel
Conext Gateway
Conext Battery Monitor
Conext XW MPPT 100-600 Charge Controller

Currently have 5800watts of PV.
I can add more PV panels to obtain more watts, but the Conext XW MPPT 100-600 Charge Controller seems to be limited to 100A.

I can’t see how to add a second Conext XW MPPT 100-600 Charge Controller, there is no place to connect a second Conext XW MPPT 100-600 Charge Controller to the Conext XW+ Mini Power Distribution Panel I have.

Do I need to replace the Mini-PDP with the larger Schneider Electric 865-1015-01 Conext XW+ Power Distribution Panel, so as to be able to connect a second Conext XW MPPT 100-600 Charge Controller?

I can open a tech support question w/ Schneider, but the past responses from Schneider tech support have been like trying to contact Microsoft for tech support.......

Anyone know of any Schneider vendor that knows anything about the system and it's options?
 
I'm not familiar with the details of adding Schneider equipment but ...

You can generally over-panel an MPPT SCC, and power harvesting will clip at maximum output.
If you parallel two arrays of panels having different orientation, you can put in panels that would be 140% of maximum output without losing any - instead you get power for more hours. That's assuming 90 degrees or 6 hours difference in orientation.
That should allow about 10kW of PV to be utilized.
 
"Supports DC coupled and AC coupled off-grid and grid-tie architectures"


If that is true for your model, consider AC coupling with a GT PV inverter (e.g. Sunny Boy and others that support frequency-watts) rather than DC coupling.
 
out back has a double breaker that gos in place of the single breaker . Your second charge controller pls gos there .
I think there is a second shunt that the neg line runs thru but I just don’t remember .
If you call Arazona wind and sun the will know what parts you need and can get them for you ,if you buy it thru them they will support the product product
 
I have Schneider equipment, but my only personal experience with trying to contact them with a question was an exercise in futility. I've since realized that they seem to have decided support to DIY / consumer questions and issues was not where they wanted to go. As a company, they have really turned towards support to professional installers exclusively. I think that explains why their equipment changes so slowly, and they would never consider consumer-friendly features like Bluetooth enabled equipment. They would much rather your stats and controls go up to the cloud where a certified professional can support your needs.

Even though I don't have any Victron, I kind of see Victron as the anti-Schneider, in terms of DIY / consumer friendliness.

Anyway, I guess I'm no help. I just think you will find it more difficult to get help unless it is here on the board from fellow Schneider users. I am one, but can't help on this one.
 
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It's on page 38 of the installation document for the charge controller. Took me just a couple if minutes to find it. It's recommended to have a Xanbus connection between the two controllers, so they are communicating with each other

To start though we should discuss in more detail your actual needs. You NEED to put a 6800W load on your inverter? Is this continuous, or sporatic? I've always used the 2X rule in all my designs, so if you really need 6800W of power, then you really should have put in two 6800W inverters, running in parallel.

And, you don't need to have 6800W of panels to run a 6800W load. I'd say it's more like 13,000W of panels. Why? Because at any given moment, you really can not expect a panel to put out it's rated output. It's a good planning idea to never expect rated output.

Keep in mind that what you are working with is pen and paper specifications. In the real-world, things can be different. At any given moment, I can flip breakers that would bring a total of 7500W of panels online. Does that mean that 7500W of electricity is flowing through my system? No way! I'm over-paneled, but I have arrays facing either SE, S, or due W, and I never see all the potential power at any given moment.
 
I don’t need the full 6800 watts all the time, but would like to have the capacity available.
Here is a typical week’s power use:
iotawatt_typical_week.png
I have considered adding a second inverter, on page 27 of this document, looks like with 2 XW Pro 6848’s I could run 12-13.6KVA, and peak @ 14.4kVA.


The system is limited by the inverter HW, there is an internal relay, max is 60A.
The document shows how to add an external contactor when more than 2 inverters are needed.
That seems like a band-aid solution that they skeched up on the back of a nakpin in a bar. (Yes, guilty of the same thing)

I have room to do this, if necessary:
Not shown is the charge controller, it may be possible to add a second CC w/ this HW configuration.
two_inverter_config.png
Reaching the limits of what a single charge controller can do.
Adding more panels this Winter, will have 3 parallel strings of 10S, total of about 11kw @ 28A @ 440vdc.
There is about 1/2 acre available for adding more ground mounts.
Really intrigued at the method of having some arrays pointing West to catch the setting Sun!
 
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Here's a pic of my latest ground mount design. That's the one pointed West. It can rotate, and I have it rotated due West, to supply late afternoon power. Since my primary array group is in a East to West straight line, only the westward most array could be rotated due west. It's only got four 250W panels on it now, because my raw array voltage is standardized around 120VDC. I could have put in six panels by rotating them in landscape instead of portrait, but I would have had to wire them in 3S2P at 90V.

I've already purchased the steel and the panels to create one more westward array, which will be positioned due South of the first westward array.
 

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I don’t need the full 6800 watts all the time, but would like to have the capacity available.
I mean. I understand why people don't have batteries but...

Isn't that what batteries are for? That and storing the excess power you generate when not pulling the panel limits.
 
I know, but just hoping to preserve the life of these batteries.
Would rather have LOTS of PV feeding the load instead.
Not sure how many "cycles" the batteries can endure, but I am sure that I would like to avoid changing them out, as long as possible.
It was an all day event, driving to Miami to pick them up, plus having to come up with a way to handle them w/o causing a 911 call.

batterycrane.png
 
You can add more charge controllers tied to the common battery / inverter bus if the settings are all the same. If there are not enough spaces for breakers in your power distribution panel you could change to the larger Schneider PDP or check into Midnite Solar distribution panels. You might be able to get a Midnite panel that will hold the new breakers and then tie that into your existing PDP. Arizona Wind & Sun has all this stuff as @JoeHam suggested. I have found them to be very helpful.

Currently I run 3 of the XW-MPPT-60 charge controllers and an older XW6048 with the larger PDP. Everything wires up with plenty of space. I have two new MPPT-80-600s to support more PV modules in the near future. The 600V breakers take two slots so I'll be in a similar situation where there is not enough room in the PDP for everything. I'll probably add a second PDP and tie them both into the same battery bus since I also have a second inverter for a second home that is under construction now. All the hardware communicates over Xanbus but I may run into bandwidth issues with too many devices when the new charge controllers and inverter are added...

You have probably already seen it, but just in case here is a doc that explains how to parallel XW6848 inverters:
XW Pro Multi-unit Design Guide

It doesn't help me since the older XW and the new XW+ / XW Pro cannot be paralleled.

For late day summer sun I plan to eventually mount some panels vertically on the end of the barn since it faces west-northwest. The main PV array is set at a fixed angle for winter so in the middle of summer the sun actually sets behind the array. I built a ground mount using pressure treated 4x6, 1/2" all-thread and unistrut as shown in the attached pics.
 

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To me, this looks like an ideal situation for AC coupling. According to my understanding, you can add up to 6500 watts of AC coupled panels to the XW6048. Using micro inverters, (I recommend Enphase) you'll be able to get your additional AC power (during solar hours) and your DC coupled arrays will continue to operate according to your programmed charge parameters. Modern Schneider equipment can regulate the AC charge input by variable frequency shifting (provided you have compatible inverters) and you won't need another expensive 6048 or charge controller - or have to reconfigure your existing distribution equipment.

The additional power will come into the AC output part of the system - when you use the power, it is highly efficient (no DC-AC conversion). If you don't use the power, it will add charge to your battery (somewhat less efficiently).

I speak from direct experience. My off-grid Schneider system:
Conext SW 4024
Conext Power Distribution Panel
Conext SCP - System Control Panel
Conext Combox
Conext MPPT 60-150 Charge Controllers (2)
3000watt DC coupled array (1500w facing south, 1500w facing west)
3000watt AC coupled (*legacy Enphase M215s) array (3000w facing southeast)
*on/off frequency shifting only - if/when the M215s fail, I'll replace them with more modern Enphase that can do variable shifting.
20kwh LFP battery bank

Everything works flawlessly. As I write this, I am running two air conditioners (one 240v mini-split & one 120v window unit) using that system. I routinely charge my car, do laundry, use microwave and kettle, and handle refrigeration with that system. I installed it myself in 2015 and have not had any downtime (except when I botched a firmware upgrade - Schneider tech support walked me through that one).

You must be certain however, that your battery bank is sized to take the momentary full output of the AC array - as frequency shifting is not instantaneous. The DC controllers are much more nimble in buffering the input/output of the different arrays.

Best of luck in your expansion.
Conext install.JPG
 
Very nice looking system!
Here is my first effort, so far:
Solarelectronics2021-07-18 at 14.34.40.png
I have read about AC coupling, and tried to figure out what it is by watching some youtube videos and reading some descriptions.
I still have no idea what it is, or how it works.
Might as well be a description of investing in derivatives…..

Until I find someone that can explain it to the mind of a 5 year old,
I will endeavor to persevere in my dumb.
 
Nice work. These might help with the AC coupling thought process. I am barely able to keep up with a five year old, myself.
 

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Here's a pic of my latest ground mount design. That's the one pointed West. It can rotate, and I have it rotated due West, to supply late afternoon power. Since my primary array group is in a East to West straight line, only the westward most array could be rotated due west. It's only got four 250W panels on it now, because my raw array voltage is standardized around 120VDC. I could have put in six panels by rotating them in landscape instead of portrait, but I would have had to wire them in 3S2P at 90V.

I've already purchased the steel and the panels to create one more westward array, which will be positioned due South of the first westward array.
Nice work. Did you use an existing design or design yourself? Did you happen to sink any ground rods when you sunk the pole? I am concerned with lightning strikes here in NH. I know there are conflicting opinions about a local ground rod or connecting ground back at the service enterance at the breaker panel. Have you given any thought to parking the array when a hurricane happens? (assuming your in a hurricane zone. Thanks for the pics.
 
Very nice looking system!
Here is my first effort, so far:
View attachment 63857
I have read about AC coupling, and tried to figure out what it is by watching some youtube videos and reading some descriptions.
I still have no idea what it is, or how it works.
Might as well be a description of investing in derivatives…..

Until I find someone that can explain it to the mind of a 5 year old,
I will endeavor to persevere in my dumb.
I might be a little concerned with lead-acid cells under inverters if inverters are pulling air through them. I worked for inverter company and have seen first hand how caustic atmospheres can destroy PCBs. Otherwise looks great!
 
@pvdude @GVSolar nice looking installs, much better wiring management than my setup. I'll clean it up one day... ;-)

GVSolar's suggestion of AC coupling sounds much better since with that much PV input to charge controllers it will be easy to fry your batteries. You can limit the charge current from the CC but that defeats your intent to have all the output available for heavy AC loads. It will be fine once the CC goes into float mode but during bulk mode the charge current could be quite high. Based on your pics, I assume your battery bank is 48V at around 400AH. The C/10 charge rate for that bank is only 40A. When discharged you might push it to C/5 or 80A. Charging at >100A will not be good unless you have a lot more batteries. Also, pulling around 12kW from a 400AH battery bank for very long will not be good. AC coupling will only provide more AC power which is perfect. I already have the second inverter and charge controllers or I might have gone that way.
 

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Yes, Rolls tech support warned me about battery damage, as the CC can output 100A.
batteries are 48 vdc, 445Ah.
I have not yet set up any limiting, as I have never seen more than 95A @ 53vdc going into the batteries, and that is only for a few seconds, when full Sun hits the PV array, after a period of shade causing battery draw down.
Typically 30-50A is the battery charge rate, and that does not last too long, as the batteries have not yet gone below 90%.

This is an example of the typical day power flow, nice gradual ramp-up of battery charge in the morning.

Screen Shot 2021-09-08 at 20.36.21.png
 
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